As a result of different diseases, the larynx of the diseased must sometimes be removed by surgery. The trachea is attached to the neck forming a so called tracheostoma or an artificial opening into the trachea leading out into the front portion of the neck, so as to make possible breathing. Due to these measures the ability to speak is lost.
In order to restore the ability of speech to a certain extent, it is possible, by means of surgery, to open a fistula between the oesophagus and the trachea to direct air from the lungs, through the fistula and to the oral cavity. This fistula must always be closed, except when air is admitted into the pharynx, because food and liquids entering the oesophagus through the mouth must be prevented from entering the trachea and further into the lungs. For this purpose, a voice prosthesis member may be inserted into the fistula. The voice prosthesis member may comprise a tubular element having a through hole and a one-way valve. A retaining member ensures that the prosthesis is kept in place. The one-way valve permits air to pass from the trachea to the oesophagus when a certain opening pressure has been reached in the trachea, but it is completely closed in the reverse direction. By temporarily closing the tracheostoma, air may be directed to flow, under the pressure of the lungs, through the hole of the voice prosthesis member into the pharynx, so that the user is able to speak. A voice prosthesis of this type is, for instance, disclosed in U.S. Pat. No. 5,578,083.
However, a device of this type has a relatively small inner diameter in relation to the outer diameter, so that it from an efficiency point of view is not optimal. More precisely, it is important to have as large smallest inner diameter as possible in order to allow high airflows through the prosthesis. A large smallest inner diameter of the prosthesis also considerably improves the quality of voice produced by the user. On the other hand, it is desired that the outer diameter of the prosthesis is as small as possible due to the requirement that the fistula should not be too large, as otherwise complications may occur.
U.S. Pat. No. 5,314,470 discloses a voice prosthesis with an integrated support ring. The support ring serves as a seat for the one-way valve, which is of the flap valve type. The ring is located in close proximity to the valve while the other walls of the voice prosthesis are relatively thick in order to withstand forced induced by the fistula and to ensure that the fistula does not collapse when the voice prosthesis is in place. Therefore, the voice prosthesis disclosed in U.S. Pat. No. 5,314,470 does not have an optimal ratio between maximal outer diameter of the through passage and the smallest inner diameter of the voice prosthesis. The voice prosthesis according to U.S. Pat. No. 5,314,470 is of the so-called in-dwelling type, which is inserted more or less permanently by a surgeon. It is normally not removed, but is cleaned in place. The prosthesis has relatively rigid flanges, which keeps the prosthesis firmly in place.
Another type of voice prosthesis is of the so-called non-in-dwelling type, which may be removed for cleaning and then reinserted by the user.
During this procedure, there is a risk, especially when the user performs the removal or insertion of the prosthesis, that the prosthesis is dropped into the oesophagus, which is less dangerous as the prosthesis most often passes the intestines without problem, or into the trachea, which may be a major problem for the user. When such a dropped prosthesis reaches the lungs, it may have to be removed by surgery. Therefore, some previously known voice prosthesis are equipped with safety straps that remain attached to the prosthesis after insertion, and which are led out of the stoma and taped to the skin of the user. However, one problem related with these straps is frequent leakage of respiratory gases passing under or beneath the tape. Another problem is that insertion of the prosthesis, which often is done by means of an insertion tool onto which the prosthesis is releasably attached, is cumbersome for the user, since the user has to control both the positioning of the prosthesis in the fistula and the strap requiring the use of two hands, see for example U.S. Pat. No. 5,064,433.
Thus, there is a need for a new and improved voice prosthesis, as well as an improved insertion tool therefore and a related insertion method.